Still don’t see an actual way to contact them from their site. When I select contact is it just brings up a map with what I am assuming is their location
I noticed you posted this here too, so I will reiterate what I did to make my own out of acrylic sheet. You can bend easily with a butane torch and cut out the teeth with a drill and jigsaw or a dremmel.
I drilled my tank myself and put 2 stand pipes in a corner for a corner overflow. Then I just had to make a sort of obtuse L-shaped weir and connect it to the sides and bottom of the tank to create the “box”. For a rear overflow, you should be able to make a U-shape and connect to the tank similarly. The bottom of the tank served as the bottom of your box, so you only need to make 2 or 3 sides with the acrylic, depending on whether it is in the corner or on the back wall.